Hydraulic control device



Dec. l, 1931. R. 1 FELLMANN ETAL HYDRAULIC CONTROL DEVIUE Filed June 16,` 1928 Patented Dec. 1, 1931 UNITED STATEsv PATENT goI-rlcrza ROBERT LEON r1:LLMAIxIN -AND MARIE CAMILLE GEORGE; or GoLBEY, NEAR EPINAL,

` YFRANCE HYDRAULIG CONTROL DEVICE Application filed .Tune 16, 1928, Serial No. 286,016, and in Germany .Tune 28, 1927.

tain degree when the loa-d ofthe engine to,-

be regulated becomesgreater orvice versa.

For this purpose, when there is areductlon or an increase of the load, the sleeveof the centrifugal governor and thedistributor ofV the servomotor must be left, afterregula-' tion, 'in the same reciprocal position as before the variation of 'the load. These elements must l undergo arelative constant movement corresponding to the admissible increase or reduction of speed.

According to the present invention,'this result is obtained in the following manner:

A delivery tube,vthe orifice of which is controlled by the sleeve of thecentrifugal governor, slides in the hollow piston rod of the servo-motor. This tube and the hollow piston rod are interconnected yby means of a dieren'tial nut. The part of this nut corresponding to the sliding tube is in the form of a vsocket which slides to the interior of the other part of the nut between springs and which is subjected to the action of a dashpot,

the piston of which is carriedby the hollowv pistonV rod of the servomotor. j

The differential nut may be arranged -so as to be conveniently set in rotation by hand for starting en route.

The accompanying y the subject matter of the invention.

Figure 1 represents diagrammatic'ally a constructional form of the subject matter of the invention adapted for regulating a hydraulic turbine.

Figure 2 represents a detail of Fig. 1 in an external view instead of a section.

The main piston 1 moving in the cylinder v1a is subjected on one of its faces to thfe'action of oil under pressure which is admitted drawings show acon-k 1 v Y u structionalV form of the device constituting: vdisplacements of slight amplitude on the tube 8 bythe action or eect of the control ofV tothe cylinder through the tube 2 and the pressure of which may be determined by: means of a. pressure gauge 8.

The pressure of oil is produced by a pump having gear 14, and taking the lliquid into the frame 22. The shaft 14a of the pump may be controlled by means of a belt 14?) through the shaft 15a of the `turbine 15 to be regulated. On thev face receiving the pressure the piston lcarri'es a rod 4 extend-V ing through the headof the cylinder 1a.

. The said rod is connectedlby a connecting rod 24 to the slide valve 25 of the turbinel to be regulated. @n the opposite face, the piston 1 communicates with the atmosphere through an lorifice 20 formed in the wall of the cylinder 1a. f

The rod-4; carriesa plate 10b againstwhich bears a spring surrounding the cylinder 1a. This spring is of sufficient strength to effect theclosureof the turbine 15'when the foil pressure has to be rendered ineffective.

On its face in communication with the at! mosphere, theA piston 1 carries a tubular rod 6, the central passage of which communi cates through transversechannels with the part of thev cylinder receiving the oil. 'Within the hollow rod' telescopes a tube 8 connected to the saidl rod by a keying 19 preventing the tube 8 vfrom rotatingk and restrain ing the same to a rectilinear movement relative to the axis of the rod 6. The tube 8 is bent and its extremity communicates with theexterior through small orifices 9 allow-l said centrifugal.governor 10a Aactuated through the `medium of shaft 10b and belt 10c by theinain shaft 15aof the turbine 15 to ,be regulated. '-7 Y j Thefrod ,6 is .externally threaded at a high pitch, aslis'indicated in F ig. 2 in an eX- ternal View, these threads engagingrwith the internal threads ofza sleeve 11 adapted to rotate but immobilized in the longitudinal direction by a ball-bearing step 12 placed in the cover 1b of the cylinder 1e and arranged in such manner that it can undergo pressure in both directions, the sleeve 11 having shoulders where it projects from the cover 1b.

The end of the hollow rod 6 of the piston 1 forms a small piston 264 which moves Vin the bore of the sleeve 11, the interior ofthe sleeve 11 being always filled with oil without pressure. vThe piston 26 has a smallv orifice 27 while the sleeve 11 communicates with the left part of the cylinder 1a where there is no pressure through the small orifice 21. The whole forms an oil brake or dash- 1;)Otl l p n There is also provided in the bore of the sleeve 11 a socket 28 likewise constituting a piston. A

The socket 28'Inay have a larger diameter than the piston 26 so that their strokes are different when the piston 26 acts ,either by pressure or by vacuum on the socket 28.

This socket 28 is screwed on the tube 8 by a thread with afine pitch 13`. V The pistonsocket 28 carries a long key/18 while the i sleeve 11 has a groove at 24 so that the socket 28 is entrained by the rotation of theV sleeve 11 wherein it is adapted to slide. On each side of the grooved shoulder r24 of the sleeve vl1 there are two compression 'springs r 29 "which always tend to restore the piston-V socket 28 to an invariable'mean position.

Atoot-hed wheel 16 is mounted 'on the sleeve 11. This wheel is controlled by a Vworm 16a. The worm may be disengaged from the wheel by means not shown in the drawings. Vhen the worm is engaged by its wheel, it is possible to operate by hand the valve 25 of the turbine 15 through themedium of the sleeve 11, screw 6, rod 4 and the connecting rod 24.

When worm 16a is disengaged, the operation of the valve is automatic as will be eX-` plained later. Y The mechanism with the worm serves only for starting because it is sufficient, in order to stop the turbine, to produce a drop of the oil pressure by lifting the valvey 30, the spring 5 ensuring the closure of the valve 25'." Said valve 30 is mounted on a stem 31 jointed to a handle 32 articulated at 33; When valve 30 is lifted from its seat through handle 32, a certain quantity of oil is allowed to liow back through pipe 34 to tank 22.

Then the valve 30 is not lifted by its handle 32, it is subjected to the action of a compression spring 34 and constitutes a safety valve for the pump 14. A spiral coiled spring 17 attached on the one hand to the sleeve 1l and on the other hand to the cover 1b con- V`stantly maintains the same faces of the threads ofscrew 6 and of theinternal threads of sleeve 11 in lengagement with each other, thereby automatically preventing play' between said threads, which play would af-Y -16a byihand, vrwhich is'then disengaged as stated above.

The apparatus being suitably regulated,

'the equilibriumV established between the driving force andthe resisting force for a given speed andthe operation is automatic.

It is assumed that no variation of the load is produced and that the speed remains constant. The oil pressure produced by the pump 14 acts on the right face ofthe piston l for eq'uilibrating the force arising from the mechanical'resistance of the valve 25 and that of the compression spring 5 -which tends to'closeit. The oil under ,pressure passes through'the openings 7 then through the telescopic tube 8 and is Vfinally discharged through the' orifices 9 partiallyy stopped by the sleeve 10 of the centrifugal governor 10c. The oil is finally discharged at a speed whichl depends 'on its pressure in order to drop again into the frame22 forming a container where it will be recovered indefinitely by the pump 14. I The mechanical resistance of theV valve 25. from`the openingfto the closure as well as that of the antagonistic spring 5 vary for each position grconsequentlthe value of the oilv pressure varies from the opening to the Closure.y `However', the position ofthe valve inV 'consequence of the mechanism, the operation of which will be described later, is not dependent on the conditions of lforce and pressure but on the position of the pilot socket 10 of the centrifugal governor 10a.

When the pilot socket 10 of the centrifugal governor 10er/fis displaced to therigli't under the influence' of an increase of speed, consequent to a decrease of load of theturbine 15, it'will open the outlets 9 of the tube 8 to a greater'extent. y The oil pressure decreases on theright vface of the piston 1 and the compression spring 5 Vdisplaces to the right all the movable parts: piston, connecting rod, and regulating ring 25. j y

The piston 26 also moves tothe vright and creates a vacuum in the bore of the sleeve 11 load beenjeffected; as has been provedby.

there would result therefrom oscillations ofl a longer or shorter period which only slowly establish the equilibrium. lowever, the socket piston 28 is also brought back to the lett under the action of the springs 29 at the same time asfthe socket 10 moves to the left. T'lhe ori lice 9 and the socket 10 maintain their respective positions and the speed is restored to normal without the position ot the piston l and L,hat oi3 the valve 25 being varied with regard to the regulation. T the speed has undergone a decrease instead or" an increase, the same n'iovements will be produced in the opposite direction.

T the operation of the apparatus should terminate there, the speed would be the same tier the variation from norma-l. This fact a o is inadmissible in the majority .of the cases e pecially when it is a question of electric gene;L ting setscoupled in parallel.

lt is necessary to make the final speed slightly different atter thel variation Jrom normal so that each position ot the valve corresponds to a diierent position of the centrifugal governor in a Zone which is greatly reduced in consequence of the displacement.

ln or( er to obtain this result, a part 13 of the tube 8 is threaded with a fine pitch as shown in Fig. 2; the sleeve 11 being set inv rotation by the screw 6, also rotates the socket piston Q8 owing to the keying 18 on the piston. The rotation of the piston 28 causes a certain displacement ofA the tube 8 in the desired direction so that a definite position of the tube 8 corresponds to each position of the piston 1 and the valve 25. The displacement or" tube 8 is very slight relativeto that of piston 1 owing to the difference of the pitches of the threads 6 and 13. Consequently.l the oriiice 9 has slightly ditl'erent position each time a regulation has been effected, i. e., the tube 8 and the openings 9 do not return eX- actly to their starting point after the variation which necessitates for the new regulation a slightly ditlerent speed according to the loads ot the turbine. This is what is termed a certain degree of statism. Y

Tt is understood that the de vicel constituting the subject matter of the invention may be applied not only to a hydraulic turbine as described but to any other driving engine. Having described our` invention what we claim as new and desire to secure by Letters Patent isy A control apparatus of the type described comprising in combination a cylinder (1a), a piston (1) in said cylinder, an inlet for fluid pressure on one tace of said piston, a spring (5) adaptedto oppose the action of the fluid on this piston, a hollow rod (6) on the other face of said piston communicating with the irst face, a sliding tube (8) keyed at the interior of the hollow rod, a discharge opening in said tube, a closure member (10)k actuated by a centrifugal governor to control the discharge opening (9) of said sliding tube, a threading on said hollow piston rod, a tin-er threading on the sliding tube, a rotatable sleeve carried by the cylinder and having a threading engaging with that of the hollow piston rod, and an enlarged portion (26) at the end of this rod sliding at the interior of said sleeve, a narrow passage (27) in said enlarged portion, a threaded sleeve (28) engaging with the threading of the sliding tube keyed in the rotating sleeve and adapted to slide in this sleeve, and springs actingrin the opposite direction on said sleeve.

2. A control apparatus of the type described comprising in combination a cylinder (la), a piston (1) in said cylinder, an inlet for fluid pressure on one tace of said piston, a spring (5) adapted to oppose the action of the fluid on this piston, a hollow rod (6) on the other face of said piston communicating with the first face, a sliding tube (8) keyed atthe interior of the hollow rod, a discharge opening in said tube, a closure member (10) actuated lby a centrifugal governor to control the discharge opening (9) of said sliding tube, a threading on said hollow piston rod, a liner threading on the sliding tube, a rotatable sleeve carried by the cylinder and having a threading engaging with that of the hollow piston rod, and an enlarged portion (26) at the end of this rod sliding at the interior of said sleeve, a narrow passage (27) in said enlarged portion, a threaded sleeve (28) engaging with vthe threading of the sliding tube, keyed in the rotatableL sleeve, adapted to slide in this sleeve, springs acting in the opposite direction on vsaid sleeve and means (16) to rotate ksaid sleeve manually.

In testimony whereof we hereunto aliix our lll) J Ril 

